Flooded nip coater pan assembly



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32 INVENTOR.

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ATTORNEYS United States Patent 3,487,813. FLOODED NIP COATER PAN ASSEMBLY Lester M. Hill, 2255 Prairie Road, Beloit, Wis. 53511 Filed Oct. 15, 1963, Ser. No. 316,293 lut- Cl. Bc 3/12 US. Cl. 118-249 ABSTRACT OF THE DISCLOSURE 3 Claims This invention relates to improvements in devices for coating traveling webs of paper and the like and more particularly relates to an improved pan and applicator roll support structure for coaters of the flooded nip type.

The present invention has as its principal objects to provide an improved form of flooded nip coater arranged with a view toward ready threading of the paper web to be coated through the coater and simplicity and eificiency in construction and operation.

A still further object of the invention is to improve upon flooded nip coaters in which a paper Web travels about a backing roll, by movably mounting the applicator roll and coating bath pan of the coater for movement toward and from the backing roll, and by providing an engaging connection between the coating bath pan support and the applicator roll support for supporting the applicator roll in nip defining relation with respect to the backing roll of the coater, and accommodating withdrawal of the applicator roll upon withdrawing the coating bath pan from the backing roll.

Another object of the invention is to improve upon the flooded nip coaters heretofore in use for coating traveling webs of paper and the like in which the coating bath pan and applicator roll may be freely withdrawn from the backing roll of the coater and in which the applicator roll is maintained in nip defining relation with respect to the backing roll by adjustable stop means on the supports for the coating bath pan, and accommodating withdrawal of the coating bath pan and applicator roll from the backing roll, and in which the coating nip spacing is defined by adjustable stops limiting movement of the applicator roll toward the backing roll.

Still another object of the invention is to provide a novel sealing and supporting arrangement for coating pans and the like, in which the sealing means for the ends of the pans is under a substantially constant relatively light pressure during operation of the apparatus and is maintained during rethreading of the apparatus, and is only broken when the end dams are removed from the coater pan for washup.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawings wherein:

FIGURE 1 is a view in side elevation of a nip coater constructed in accordance with the principles of the present invention with certain parts broken away, showing the applicator roll and coating bath pan in operative coating po itions;

FIGURE 2 is a fragmentary view in side elevation of the flooded nip coater shown in FIGURE 1, showing er: l

the coating pan withdrawn and positioned for cleaning;

FIGURE 3 is a detail sectional view showing the dam for the coating bath pan mounted on the applicator roll and taken substantially along line III-III of FIGURE 1;

FIGURE 4 is a fragmentary transverse sectional view taken through the coating bath pan; and

FIGURE 5 is a partial fragmentary side view of the coating bath pan with certain parts removed.

In the embodiment of the invention illustrated in the drawings, 10 generally designates a coating device, which comprises a backing roll or drum 11, wrapped by a traveling sheet or web W, and an applicator roll 12 picking up coating material M from a coating bath pan 13, and applying it to the sheet W on the backing roll 11.

The backing roll 11, applicator roll 12 and coating bath pan 13 are mounted on a frame 14 including parallel spaced posts 15 suitably connected together. The rotary drum or backing roll 11 is journalled at its ends in hearing supports 17, mounted on support structures extending forwardly of the posts 15. The rotary drum or backing roll may have a resilient face and is driven by suitable drive means, such as an electric motor (not shown), in a conventional manner, to attain a predetermined surface speed of the periphery of the backing roll 11.

Spaced circumferentially from the outgoing side of the nip between the backing roll 11 and applicator roll 12 is a doctor blade 18 mounted on a blade support 19 extending from a doctor back (not shown), which may be trunnioned at its opposite ends and. adjustably moved in a conventional manner, to vary the pressure of the blade 18 on the traveling web W and to vary the angle of the blade with respect to the web. A drip plate 20 ex tends downwardly of the incoming side of the doctor blade for the length thereof and is positioned to discharge surplus coating material into an overflow trough 21 extending along the top portion of the coating bath pan 13.

The applicator roll 12 may be driven from a suitable motor (not shown) and is longer than the width of the web on the backing roll and extends substantial distances along the exposed edges of the surface or periphery of the backing roll 11. The applicator roll 12 may be rotated in the direction of web travel or may be rotated in an opposite direction for certain coating applications. A nip N formed between the backing roll 11 and the applicator roll 12 may be such as to merely permit contact between the web W and the applicator roll 12, to the extent necessary to apply the coating material M at the nip N.

The exent of contact between the applicator roll 12 and the web W and their relative speeds may be correlated so that the web W removes coating material from the surface of the applicator roll 12 slightly more rapidly than the coating material is brought to the nip N, with the result that the coating material M is spread much more thinly on the web W than on the surface of the applicator roll 12. The applicator roll 12 is partially immersed in a bath of coating material M contained in the pan 13 and the amount of coating material M that is filmed onto the up running side of the applicator roll 12 may be controlled by variations in level of the coating material M in the pan 13, which level may be controlled under the control of an adjustable weir 22, so that the desired amount of coating material M is applied to the web W; and as has been pointed out, this amount is much less per unit of area on the web than the amount of coating material per unit of area on the applicator roll surface.

The doctor blade 18 thus serves to smooth the coating material rather than to actually remove any excess of coating material, but if any excess of coating material should occur, the drip plate 20 will return the coating ma terial to the return duct or trough 21.

The coating bath pan 13 is of a generally trough-like construction having opposite open ends closed by removable and dams 23, 23 sealed thereto by seals 24 extending along the side and bottom edges thereof and conforming to and engageable with the wall of the pan 13, as shown in FIGURES 1 and 3. The seals 24 may be well known forms of O-ring types of seal and normally engage the coating bath pan with a constant pressure, determined by adjustable stops 57. It is advantageous that the pressure be a relatively light pressure, placing the seal under just enough load to seal the ends of the pan but not undul stressing the seal.

The support structure for the pan 13 and applicator 12 is the same for each end of said pan and applicator roll so the support structure for one end only of said coating bath pan and applicator roll need herein be shown and described.

The coating bath pan 13 has the overflow trough 21 extending along the side thereof spaced from the outgoing side of the nip between the rolls 11 and 12 and in coating bath receiving relation with respect to the drip plate leading from the doctor blade 18. A similar overflow trough extends along the opposite side of the coating bath pan 13. The overflow troughs 21 and 25 are inclined downwardly from the center of the pan in opposite direction and terminate in drains 21a and 2512 respectively, said overflow troughs are closed at their opposite ends by flanges 26 extending outwardly of the pan 13 and depending therefrom. The drains 21a and 25b may drain to a suitable sump (not shown) accommodating the coating solution to be returned to the coating bath pan 13.

The outgoing side of the pan 13 has the weir 22 extending therealong. The weir 22 is adjustably mounted between the outside of the pan 13 and the inside of a plate 28 extending along said pan. The end of the plate 28 is spaced from an upwardly projecting end plate 30 of the pan and defines a notch 32 forming an overflow notch through which coating material may flow, governed by the height of the wier 22. The plate 28 is bolted to the pan 13 by nuts and bolts 28a which extend through vertical slots 22a in the weir and form a means for adjusting the height of said Weir. It should here be understood that the applicator roll 12 rotates in a clockwise direction and draws the coating material from the outgoing to the incoming side of the pan 13 toward the weir 22 and tends to build up the level of coating material on incoming side of said coating bath pan. The weir 22 thus may allow coating material to accumulate at the incoming side of the applicator roll 12, and may be vertically adjusted to attain the proper level of coating bath material.

The coating bath pan 13 is supported at its opposite ends on pan support arms 27, extending along the insides of the posts 15 and pivotally mounted on said posts on pivot shafts 29, extending inwardly of said posts. The pan support arms 27 extend beneath the pan 13- beyond the center of said pan and are pivotally connected to the flanges 26, as by transverse pivot pins 30. The arms 27 are retained in the operative position shown in FIGURE 1 and are lowered to a position to accommodate cleaning of the pan 13- as by a fluid pressure cylinder 31 having a piston (not shown) therein and a piston rod 33 extensible therefrom. The piston rod 33 has a connector 35 on its outer end pivotally connected to the arm 27 as by a transverse pivot pin 36. The cylinder is trunnioned to the rear and inside of the post 15 on trunnion pins 37, mounted in trunnion supports 39.

The coating bath pan 13 is held in the upright position shown in FIGURE 1 and is pivoted about the pivot pins 30 for cleaning, when in a lowermost position, as by a fluid pressure cylinder having a piston (not shown) therein and a piston rod 41 extensible therefrom. The cylinder 40 has spaced ears 43, 43 extending from its head end along opposite sides of a connector 44 and pivotally, connected thereto as by a pivot pin 45. The connector 44 is adjustably mounted on a bracket arm 46 mounted on the inside of the post 15 in a suitable manner.

Thus, as the coating bath pan 13 is lowered by the admission of fluid under pressure to the piston rod ends of the cylinders 31, at each end of said coating bath pan, fluid under pressure, such as air, may be admitted to the head ends of the cylinders 40 and pivot the coating bath pan 13 about the axes of the pivot pins 30 into the cleaning position shown in FIGURE 2.

The applicator roll shaft 25a extends through and is suitably sealed to the end dams 23 adjacent itsopposite ends and is mounted at its opposite ends in bearing supports 16, 16 in bearings 49, 49. The bearing supports 16, 16 are suitably carried on the free ends of lever arms 50, 50 mounted on the insides of the posts 15 on the transverse pivot shafts or pins 29. Each arm 50 has an upright ear 51 extending upwardly therefrom adjacent its forward or outer end portion. The upright ear 51 has an elongated slot 53 extending therethrough, registerable with a pin 55 removably mounted in an car 56 depending from the support 17. The pin 55 limits movement of the applicator roll 12 with respect to the backing roll 11 and retains the applicator roll 12 in an elevated position when the pan 13 is moved to the cleaning position shown in FIGURE 2.

The applicator roll is maintained in the required nip relation with respect to the backing roll 11 by adjustable stops 57, herein shown as being machine screws threaded in the top surfaces of the arms 27 and locked thereto as by lock nuts 59. The heads of the machine screws 57 abut flat abutment surfaces 60 on the undersides of the bearing supports 16, and support said bearing supports and the applicator roll 12 on the pan supporting arms 27, and accommodate lowering of said bearing supports and applicator roll 12 upon lowering movement of the coating bath pan 13, upon the admission of fluid under pressure to the piston rod ends of the cylinders 31 and also maintain the load on the seals 24 at substantially no load to seal the ends of the pan 13 without placing undue pressure on said seals.

Movement of the applicator roll 12 toward the backing roll 11, and the nip between said applicator roll and said backing roll is limited and determined by micrometer stops 61 on the opposite sides of the bearing supports 16 from the stops 57, and engageable with bearing surfaces 63, shown as extending perpendicular to the axes of said micrometer stops. As shown in FIGURE 1, the micrometer stops 61 are carried by studs or bolts 64, threaded in brackets 65, depending from the bearing supports 16 and locked thereto as by lock nuts 66. The micrometer stops 61 are of a conventional construction, commonly used in paper machinery and particularly in coaters so need not be shown or described in detail herein. These micrometer stops permit a fineness of adjustment of the nip N, it being understood that the applicator roll 12 is usually spaced from the web traveling about the back ing roll 11 with the result that the nip N is not necessarily a pressure nip, although it may be a pressure nip under certain coating conditions.

It may be seen from the foregoing that the applicator roll 12 is held in position between the stops 57 and '61 and is free upon lowering movement of the coating bath pan 13, downward movement thereof being limited only by the pins 55 retaining said applicator roll in position for threading a web about the backing roll 11.

It should here be understood that in the operative position of the applicator roll 12 for coating, the pins 55 are free from the slots 53 and from following the arms 27 to the extreme limit of movement thereof. When however, it may be desired to rethread the coating device with a new web, the pins 55 may be removed to accommodate said applicator roll to drop with the arms 27 as said arms are lowered.

A means is provided, which is selectively movable in position to limit downward movement of the arms 27, coating bath pan 13 and applicator roll 12 when the pins 55 are removed and it is desired to Iethread the device. This means is shown as being a stop 67 on the outer end of an arm 69 mounted on a pivot pin 70, extending outwardly of the associated post to the rear end thereof, and having a crank arm 71 suitably secured to the outer end thereof. A spring pressed locking pin 73 is slidably mounted on the outer end of the crank arm 71, for engagement with an apertured boss 74, locking the crank arm 71 and stop 67 in the inoperative position shown in FIGURE 1. As the pin 73 is removed from the apertured boss 74, the crank 71 may be turned to lower the stops 67 into the position shown in FIGURE 2 to engage the arms 27, 27 and limit downward movement of said arms and the applicator roll 13. In the position, the end dams 23 are sealed to the pan 13 and coating material is retained to said pan by the seals 24.

I claim as my invention:

1. In a device for coating a traveling paper web, in

combination,

a frame,

spaced bearing supports mounted on said frame,

a backing roll rotatably journalled in said bearing supports for rotation about a horizontal axis,

a coating bath pan disposed beneath said backing roll,

a pair of laterally spaced pan supporting arms transversely pivoted to said frame for movement about an axis parallel to the axis of rotation of said backing roll and spaced therefrom,

fluid pressure cylinder and piston means pivotally connected between said frame and said pan supporting arms for raising and lowering said arms and coating bath pan,

an applicator roll,

a pair of spaced roll supporting arms pivoted to said frame, for movement about the axis of pivotal movement of said pan supporting arms for lowering movement under the control of said pan supporting arms, and supporting said applicator roll for immersion in said coating bath pan,

an abutting supporting connection between said pan supporting arms and said roll supporting arms, for lowering said pan and applicator roll upon lowering movement of said pan supporting arms, and bringing said applicator roll into nip defining relation with respect to said backing roll upon raising movement of said pan supporting arms, and

a movement limiting stop connection between said frame and said roll supporting arms holding said applicator roll in a preselected position out of coating nip defining relation with respect to said backing roll, and accommodating said pan supporting arms to move out of engagement with said roll supporting arms, to withdraw said pan from said applicator roll as said pan supporting arms lower said pan beneath this preselected position of said applicator roll, said movement limiting stop connection being releasable to accommodate continued lowering movement of said applicator roll with said pan.

2. A device for coating a traveling paper web in accordance with claim 1,

wherein bearing supports are carried by said roll supporting arms, and rotatably support said applicator roll,

wherein adjustable stop means are mounted on said frame and face said bearing supports to determine the coating nip spacing between said applicator roll and said backing roll, and

wherein the abutting supporting connection on said pan supporting arms is spaced from and faces said adjustable stop means and is adjustable to engage said bearing supports with said adjustable stop means and balance the forces on said bearing supports engaging said adjustable stop means and the forces of engagement of said abutting supporting connection with said bearing supports.

3. A device for coating a traveling paper web in accordance with claim 1,

wherein the coating bath pan is transversely pivoted to said pan supporting arms,

wherein hydraulic cylinder and piston means are connected between said frame and said pan to pivot said pan about its axis of connection to said pan supporting arms, and

wherein the releasable movement limiting stop connection between said frame and roll supporting arms is a pin and slot connection, releasable to accommodate raising and lowering movement of said applicator roll with respect to said backing roll while in said coating bath pan, by raising and lowering movement of said pan supporting arms.

References Cited UNITED STATES PATENTS 3/1952 Rullo 118-249 1/ 1918 Sherwood 118224 11/1962 Walton 118-227 X UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,487,813 Dated January 6, 1970 Invent0r(s) Lester M.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 4, after 535ll", insert assignor to Beloit Corporation, Beloit, Wis., a corporation of Wisconsin-- Column 5, line 13, change "the", second occurrence, to

- -this SIGNED KND SEALED JUL 2 8 1970 45 M) Am Edward 1!. mm. It.

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